Signaling apparatus.



E. H. LNG.

SIGNALING APPARATUS.

APPLIOATION FILED 14H24, 1909. EENBWBD MAR. 1a, 1912.

Patented June 18, 1912.

2 SHEETS-SHBET 1.

COLUMBIA PLANOURAPH C0., WASHu-lG1`0NY D. C.

E. H. LONG.

SIGNALING APPARATUS.

PPLIUATION 1711.111) 11u24, 1909. RENBWED MAB. 19. 1912.

' 1,029,81 1 Patented June 18, 1912.

2 SHEETS-SHEET 2.

COLUMBIA PLANOGRAPH C0., WASHINGTON D c T OFFXCE.

EDWARDAI-I. LONG, OF LOS ANGELES, CALIFORNIA.

SIGNALING APPARATUS.

Specification of Letters Patent.

Patented June 18, 1912.

Application filed May 24, 1909, Serial No. 497,840. Renewed March 19, 1912. Serial No. 684,808.

To all whom it may concern:

Be it known that l, EDWARD H. LONG, citizen ot the United States, residing at Los Angeles, in the county ot Los Angeles and State of California, have invented a cert-ain new and useful Improvement in Signaling Apparatus, of which the following is a full, clear, concise, and exact description, roterence being had to the accompanying drawings, forming a part of this specification.

My invention relates to signaling apparatus, and particularly to that general class of signaling apparatus in which a plurality of signal-transmitting devices are associated with a given circuit. having a signal-receiving apparatus common thereto.

It is one of the general objects of my invention soto improve the apparatus at the receiving station that it may .properly and very etlectively cooperate with any operating signal-transmitting apparatus at a transmitting station.

Another general object of my invention is to provide an improved construction of the transmitting apparatus and the inter-relation thereof with thetransmission line,`so that the transmitting apparatus at each ot the transmitting stations may operate to the exclusion of lthe transmitting apparatus at any of the other transmitting stations, so that an operating transmitting apparatus may appropriate the transmission line, and thereby occasion signals at the signal-receiving station that are characteristic to the transmitting station, it being understood that the transmitting apparatus at the different transmitting stations are adapted to convey characteristic signals that will distinguish the transmitting stations from each other.

It is one of the main objects of my invention so to construct the transmitting de vices at the transmitting stations that they will not require manual attention except on the part of one who desires to transmit a signal, it being possible by means ot my invention to have the apparatus at the transmitting stations restored to normal after their operation, and in condition again to be operated.

It is another object ot' my invention so to construct and inter-relate the apparatus at the transmitting stations that but one transmitting station can be operatively associated with a transmission line at a time, so that there will be no confusion oit signals at the receiving station.

There are advantages and characteristics of construction which will more fully appear by a description of the preferred embcdiment of my invention, shown in the accompanying drawings, in which- Figure l. is a diagrammatic view of a signaling systeni equipped in accordance with the invention. Fig. 2 is a plan View ot mechanical apparatus employed at a transmitting station. Fig. 3 is a perspective view of part of the apparatus shown in Fig. 2.

Like parts are indicatedby similar characters of reference throughout the different figures.

The mechanical equipment being so well shown in the diagram, and there being so few parts shown in the other views that -are not shown in the diagram, the different views will not be separately described.

I employ a closed line circuit, which eX- tends from the signal-receiving station A to the signal-transmitting stat-ions B, C, etc., any suitable and convenient number ot transmitting stations being employed, two only being shown in detail Jfor sake of clearness and because of insufficient space to `show more. In order that the invention may be more fully understood, other stations equipped similarly to stations B C are diagrammatically suggested at B1 C1. The closed circuit that normally exist-s may be traced from the positive pole of a suitable source ot unidirectional current l, which preferably constitutes a line battery, to the normal contact l engaging a spring 3, the side 4 of the closed transmission signal circuit, the conductor 5 uniting the side 4 of the signal-transmissionV circuit with the side 6 of said circuit, the spring 7, the normal contact S, to the negative pole of the source of unidirectional current l, which is preferably a battery, the winding of a non-polarized electro-magnet or relay 9 being serially included in the side G of the transmission circuit at the signalreceiving station, the winding of this mafg- Were not desired to use a transmission line for telephonic purposes, the impedance at 5 could be omitted. I have not indicated any telephone connect-ions, as the manner of connecting telephonic apparatus between the sides'of metallic circuits is so Well knoivn to those skilled in the art. The Winding of the relay 9 is thus normally included in closed circuit and the armature of said relay or magnet 9 is, therefore, normally magnetically attracted to hold a Wheel 10 normally in an inactive position, the armature of the magnet 9 being provided with a stop 11 for this purpose, this stop engaging a notch 12 in a portion of the Wheel structure 10. A Weight 13, or its equivalent, a spring, is employed to rotate the Wheel structure 10 Whenever the detent 11 is disengaged from said Wheel structure, which disengagement occurs lwhenever the normally closed transmission circuit is opened at any transmitting station, whereupon the spring 14 is permitted to act to Withdraw the detent 11 from engagement with the Wheel structure 10.

One of the objects of my invention relates to means for governing the operation of the signal receiver located at the signal-receiving station, and While I prefer, as a signalreceiver, the use of the familiar tape recorder including an operating electro-magnet 15 and the tape apparat-us 16, I do not Wish to be limited to this form of signalreceiver, as it is obvio-us that other forms of signal-receivers may be employed to advantage in the system of my invention. The signal-receiver illustrated is included in a local circuit at the signal-receiving station, this local circuit including a source of suitable current, such as a battery 17, and Which local circuit may be traced from the righthand pole of said battery through the Winding of the electro-magnet 15, the contact 18, the contact spring 19 normally in separated relation with the contact 18, the contact spring 2O and the contact 21 normally in separated relation with the contact spring 20, to the remaining pole of the local battery 1T.

Character vheels, hereinafter to be more particularly mentioned, and each of which is peculiar to its station, are located at the different transmitting stations, so that the signal sender will, by bringing his character Wheel into operation, cause successive breaks in the line circuit, occasioning as many deenergizations of the magnet 9, and, consequently, permit-ting as many operations of the spring 14 at the signal-receiving station, and thereby causing as many closures of the contacts 18 and 19 as thereare openings caused in the line circuit at the signal-transmitting station, it being apparent that the spring 14 each time it is free to act, will bring the contact spring 19 into engagement with the contact 18, whereby the signal-receiver 15 16 is caused to convey a signal Which corresponds in character to the operated character Wheel, the elements 20 and 21 having been closed upon the disengagement of the detent 11 fro-m the Wheel structure 10, the elements 2O and 21 being provided for a purpose which Will hereinafter be more particularly set forth` I have described, in outline, the circuit which normally exists. I will now describe, in some detail, the apparatus shown at the signal-transmitting stations, and will thereafter describe some of the remaining features ofthe apparatus shown at the signalreceiving station.

At each of the signal-transmitting stations'I have shown a polarized magnet 22 Which is preferred and Whose Winding is looped into the side 6 of the transmission circuit, but which VWinding is preferably normally shunted by a shunt conductor which normally is in parallel relation With the Winding of magnet 22 and is normally looped into the side 6 of the transmission line, said shunt conductor thereby normally protecting the magnet-22. This protect-ing shunt conductor may be traced through the movable contact 23, to the stationarily mounted contact 24, the contacts 23 24 being normally in engagement. When the operating lever or handle 25 is turned against the force of the clock spring 26, the Contact elements 23 24 are disengaged, whereby the shunt about the associate magnet 22 is broken, for a purpose presently to be mentioned. When the operating lever 25 is released, the spring 26 which had been placed under increased tension as a result of the operation of the lever 25, effects the rotation of the character Wheel 27, whereby. said character Wheel is caused to open the circuit lincluding the line battery 1 as many times as there are breaks in the character Wheel to cause as many closures of the contacts 18 and 19 and as many operations of the signal device 15 16, -as has been explained. I have not deemed it important to illustrate and describe fully the mechanism for effecting the operation of the character Wheel, as such is Well known to those skilled in the art. The character wheel is enabled to perform the function of opening theline circuit, because the loop conductor at the transmitting` station including the magnet 22 also inchicles the associate character wheel and the brush 28 engaging the same. W'hen the signal is initiated at a signal-transmitting station, thev polarized magnet 22 is operated, first, because t-he contacts 23 and 2-t included in the shunt about the same are separated When' the signal is initiated, and, second, because the battery 1 then has its normal connection with the line, which is such that the polarized magnet22 Will respond to current therefrom as soon as the shunt about said ist lid

magnet is opened at 23 24. Inasmuch as the line circuit is opened by the character wheel and the connection of the battery l with the line is thereafter reversed, for a purpose which will be stated, I provide means whereby the attracted armature of the polarized relay 22 is mechanically held in the position to which it has been actuated until the signal-transmitting apparatus at the signaling station has been restored to normal. This mechanical means for holding the armature ot' magnet 22 in its attracted position desirably resides in a lever 29 pivoted between its ends and brought by a spring 30 to rest against a rotating stop 3l carried by the character wheel, the character wheel, when operated, removing the stop 3l from engagement with the arm 29, thereby permitting the spring 30 to rotate the lever 29 when the' detent 321, governed by the magnet 22, has been disengaged from the lever 29, which disengagement occurs when the magnet 22 is energized and when the signal is first initiated, that is, just as soon as the contacts 23 24 are separated. lVhen the spring 30 has thus rocked the lever 29, the nose o't the detent 321 will ride upon the lever 29 until the contact arm 23 is brought to normal to cause rotation or" the lever 29, and thereby rengagement of the detent 821 with the lever 29 and the rengagement of said lever 29 with the pin 3l, it being understood that the spring 83 effects the restoration of the armature of the magnet 22, this armature being free to be restored by the spring, inasmuch as the magnet 22 is still unsubject to the current from the battery l, whose normal connection with the transmission line is timed to occur a few seconds after the character wheel at the transmitting station has been brought to rest. From all which has been described and illustrated, it is very apparent that a number of signalsending devices along the transmission line may be operated during the time that another transmitting station has control of the line, and that the stations at which the apparatus was later manually operated will assume control of the line in the order of their succession, the station nearest the receiving station first assuming control of the line, the station next nearest the signal-receiving station next assuming control of the line, and so on throughout the waiting stations in succession. lVhile I prefer to use the shunts controlled by the switches 33 34 tor temporarily excluding the stations beyond the signaling station that has control of the line, I do not wish to be limited to the shunt switches for this purpose in all embodiments of my invention. rI`he armature of the electro-magnet 22 is held in the position to which it has been momentarily attracted, in order that the contacts 33 and 34 governed by the magnet 22, maybe maintained closed during the time that signals are beingtransmitted to the signal-receiving station, the switch 33 34, when closed, establishing a shunt or short circuit across the transmission line beyond the stat-ion from which signals are being transmitted, whereby the signal-transmitting apparatus at any stations beyond the stations from which signals are being transmitted, will interfere in no way with the operation ot' the signaltansmitting apparatus that has acquired possession of the transmission line. Obviously, the station at which transmit-ting apparatus is first used, irrespectiveof its location along the transmission line, is the station that has appropriated the line, for at that station the shunt across the line has been established at 33 34, as stated.

lIt has been shown that current from the line battery 1 must flow through the polarized magnet 22 in a particular direction, in order to establish the shunt at 33 34 across the transmission line to prevent the transmitting apparatus at other stations from operating. In order, therefore, to prevent the magnet 22 at any other trans- 'mitting station between the transmitting station that has appropriated the line and the signal-receiving station from being subsequently operated, the connection of the line battery l with the line must be reversed, it being permissible to reverse the connection of this battery with the line, inasmuch as the` armature of the polarized magnet 22 at the station which has appropriated the line is being mechanically held after its attraction at the signal-transmitting station. In order that the connection of the battery 1 with the line may be reversed immediately after said battery has operated the polarized relay 22, I preferable employ a pole-changing switch, of which the elements 2 3 7 8, that have been mentioned, form parts, the springs 3 and 7 having alternate contacts that are connected with terminals of the battery that are opposite to the terminals with which the normal contacts 2 and 8 are connected, the pole-changing switch being operated by the wheel 10 when the detent 11 releases said wheel l0, which disengagement of said detent from said wheel occurs after the armature of the polarized magnet at the transmitting station which has appropriated t-he line, has operated, whereby it will be impossible for anyone to operate the siglial-transmitting apparatus at any station intervening between the station ioo which has appropriated the line and the the character wheel 27.

not energized and can not be energized, because of the fact that the battery 1 has previously had its connection with the line reversed. At the transmitting station which has secured possession of the line, however, the detent 35 is disengaged from the escapement 36, owing to the attraction of the armature of the magnet 22 and the subsequent mechanical retention of said armature in its attracted position, the escapement 36, through the intermediation of suitable gearing, as is well understood by those skilled in the art, governing the rot-ation of Thus, in the preferred embodiment of the invention, the lever 25, through electrical means, releases the character Wheel 27, but I do not wish to be limited in all embodiments of my invention to electrical mechanism for releasing the character wheel 27.

In the preferred embodiment of the invention, the wheel structure 10 includes a lug 37 upon which the spring structure 3,

` 7 rests, the springs 3 and 7 being mechanically united by a block of insulating material, as illustrated, whereby said springs may be simultaneously operated. 37 maintains the springs 3 and 7 under slight tension.

Referring again to the receiving station apparatus, when the wheel structure 10 is released by the disengagement of the detent 11 therefrom, the springs 3 and 7 are permitted to move toward their alternate contacts, whereby the normal connection of the line battery 1 with the line is reversed, for the purposes which have been stated. For reasons which will be apparent, it will not do to have the springs 3 and 7 engage their alternate contacts before leaving their normal contacts, and inasmuch as the circuit for the battery 1 will be broken each time the connection of the battery with the line is reversed, the signal-receiver 15 16 would be operated, unless the precaution of my invention were employed, because the magnet 9 would be denergized.

I include the contacts 2O 21 in serial relation with the local battery 17 and cause the contacts 2O 21 to be closed just after the connection of the battery 1 with the line has been reversed, the engagement of the contacts 2O 2l occurring after the contacts 18 19 have been engaged, which latter contacts are engaged upon the release of the wheel structure or during the release of such wheel structure, whereby the contacts 2O 21 are, in effect, the contacts which directly occasion the irst signal at the signal-receiver 15 16, but inasmuch as the'contacts 20 and 21 remain in engagement until the wheel structure 10 is again arrested in its normal posii tion, the contacts 18 and 19 occasion the further signals at 15 16. In the preferred embodiment of the invention, the wheel struc- The lug ture 10 includes another lug 38, which normally engages the spring 20, and whose normal position is such with respect to said spring 2O that the lug 38 escapes the spring 2O to permit said spring to engage its contact 21, preferably just shortly after the connection of the battery 1 with the line has been reversed. Conversely, when the normal connection of the battery 1 with the line is restored, the line circuit again will be opened and a false signal again will be occasioned, unless the precaution of my invention were employed, the switch 2O 21 again preferably being employed to prevent this false signal, the local circuit including the local battery 17 being opened at 20 21 when the wheel structure 10 is being restored to normal before the normal connection of the battery 1 with the line is brought about, s o that the subsequent opening of the line circuit will not be followed by the manifestation of a signal at 15 16, though the contacts 18 and 19 are brought together when the normal connect-ion of the battery 1 with the line is resumed, the circuit including the contacts 18 and 19 having previously been opened at 2O 21, as has been stated.

It is apparent that it is only necessary, under certain circumstances, to maintain the switch contacts 33 3st at a transmitting station from which signals are being sent, closed long enough to permit the reversal of the connections of the source of unidirectional current 1 with the line, for after such connectic-ns have been reversed, it will be impossible for electro-magnets 22 at other stations to be operated to release the character wheels 27 thereat, owing to the polarization of said other magnets and the change of'the direction of the current passing through the same.

IVhile I prefer to employ but one set of battery as a source of unidirectional current at the signal-receiving station, and, therefore, prefer to employ pole-changing mechanisin, I do not wish to be limited to the use of one set of battery, nor to the use of polechanging mechanism for such battery.

The apparatus of my invention may have a variety of uses. It is of particular use in connection with fire alarm service, but I do not wish-to be limited to such use.

It will be seen that I have provided a signaling system including a transmission line extending from a signal-receiving station to plurality of signal-transmitting stations, a source of current in closed circuit with the line, signal-transmitting mechanisms at the signal-transmitting.stations for operating the signal-receiving apparatus at the signalreceiving station, electro-magnetic mechanisms at the transmitting stations serving to control the relation o-f the signal-transmitting mechanisms with the line, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the electro-magnetic mechanisms from operative relation with the line, and serving, upon the transmission otl signals to bring the electro--n'uignetic mechanism at a sending station into circuit relation with the line to establish cooperative relation ot the signal-transmitting mechanism at the sending station with the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, when circuit is altered at a transmitting station, to impress current upon the line which is .not adapted to operate said electromagnetic mechanisms but which is adapted to cooperate with the signal-transmitting mechanisms to occasion signals at the receiving station.

lVhile I have herein shown and particularly described the preferred embodiment of my invention, it is obvious that many changes may be made in the preferred embodiment of the invention without departing` from the spirit ot the invention, and I do not, theretore, wish to be limited to the precise details ot construction shown and specifically described, but,

Having thus described my invention, l claim as ne f* and desire to secure by Letters Patent:-

l. it signaling system including a transmission line extending from a signal-receiving station to a plurality of signail-transmitting stations, a source of unidirectional current in closed circuit with the line, signal-transmitting mechanisms at the signal-transmitting stations tor operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to exclude other transmitting stations trom the line, polarized electro-magnets at the transmitting stations :t'or operating said switching devices, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the polarized electro-magnets trom operative relation with the line and serving, upon the transmission ot signals, to bring the polarized electro-magnet at a sending station into circuit 'relation with the line to opeate the associate switching device, the normal connection oit' the source of unidirectional current with the line being such that currentI from said source of unitlirectional current will operate the electro-magnet at a transmitting station whose signal-sending mechanism has brought said electro-magnet into circuit relation with the line, an electromagnet at the receiving station normally in circuit relation with the line, mechanism governed by the latter electro-magnet and serving, when the circuit is altered at a transmitting station, to connect unidirectional current in reverse direction with the line,

means tor holdingA the armature of the poy larized electro-magnet at the transmitting station from. which signals are being sont, in order to maintain the switching mechanism governed by the armature of said polarized electro-magnet in the condition in which said armature has placed said switching mechanism, and means whereby the signal-sending mechanism may release the armature ot said polarized electro-magnet when said signalsending mechanism has been restored to normal.

Q. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmitting stations, a source of unidirectional cur` rent in closed circuit with the line, signaltransmitting mechanisms at the signaltransmitting stations for operating' 'the signal-receiving apparatus at the signal-receiving station, Switching devices at the transmitting stations, each serving to exclude other transmitting stations from the line, polarized electro-magnets at the transmitting stations for operating said switching devices, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the polarized electro-magnets from operative relation with the line and serving, upon the tra-nsmission of signals, to bring the polarized electro-magnet at a sending station into circuit relation with the line to operate the associate switching device, the normal connection of the source of unidirectional current with the line being such that current trom said source of unidirectional current will operate the electro-magnet at a transmitting station whose signal-sending mechanism has brought said electro-magnet into circuit relation withithe line, an electroinagnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, when the circuit is altered at a transmitting station, to connect unidirectional current in reverse direction with the line.

A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmitting stations, a source ot' unidirectional current in closed circuit with the line, signaltransmitting n'iechanisms at the signaltransmitting stations for operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to exclude other transmitting stations from the line, polarized electro-magnetic mechanisms at the transmitting stations for operating said switching devices and serving to control the relation of the signal-transmitting mechanisms with the line, and serving, when energized, to cause operative association of said signal-transmitting mechanisms with the line, means governed by the signal-sending mechanisms at t-he transmitting stations serving normally to exclude the polarized electro-inagnetic mechanisms from operative relation with the line and serving, upon the transmission of signals, to bring the polarized electro-magnetic mechanism at a sending station into circuit relation with the line to operate the associate switching device, the normal connection of the source of unidirectional current with the line being Such that current from said source of unidirectional current will operate the electromagnetat a transmitting station whose signal-sending mechanism has brought said electro-magnet into circuit relationwith the line, an electro-magnet at the receiving station normally in circuit relation with the line, mechanism governed by the latter electro-magnet and serving, when the circuit is altered at a transmitting station, to connect unidirectional current in reverse direction with the line, means for holding the armature of the polarized electro-magnet at the transmitting station trom whichsignals are being sent, in order to maintain the switching mechanism governed by the armature of said polarized electro-magnetic mechanism in the condition in which said armature has placed said switching mechanism, and means whereby the signal-sending mechanism may release the armature of said polarized electro-magnetic mechanism when saidsignal-sending mechanism has been restored to normal.

4. A signaling system including a transmission liiie extending from a signal-receiving station to a plurality of signal-transmitting stations, a source of unidirectional current in closed circuit with the line, signaltransmitting mechanisms' at the signaltransmitting stations for operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to exclude other transmitting stations from the line, polarized electro-magnetic mechanisms at the transmitting stations for operating said switching devices and serving to control the relation of the signal-transmitting mechanisms with the line, and serving, when energized, to cause operative association of said signal-transmitting mechanisms with the line, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the polarized electro-inagnetic mechanisms from operative relation with the line and serving, upon the transmission of signals, to bring the polarized electro-magnetic mechanism at a sending station into circuit relation with ythe line to operate the associate switching device, the normal connection of the source of unidirectional current with the line being such that current from said source of unidirectional current will operate the electromagnet ata transmitting station whose signal-sending mechanism has brought said electro-magnet into circuit relation with the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, when the circircuit is altered at a transmitting station, to connect unidirectional current in reverse direction with the line.

5. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmitting stations, a source of unidirectional current in closed circuit with the line, signaltransmitting mechanisms at the signaltransmitting stations for operating the signal-receiving apparatus at the signal-receiving station, polarized electro-magnets at the transmitting stations, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the polarized electro-magnets from operativerelation with the line and serving, upon the transmission of signals, to bring the polarized electro-magnet at a sending station into circuit relation with the line, the normal connection of the source of unidirectional current with the line being such that current trom said source ot unidirectional current will operate the electro-inagnet at a transmitting station whose signalsending mechanism has brought said electro-magnet into circuit relation with the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, when the circuitis altered at a transmitting station, to connect unidirectional current in reverse direction with the line.

6. A signaling system including a transmission line extending from a signal-receiving station to a plurality ot signaltransmitting stations, a source of unidirectional current in closed circuit with the line, signal-transmitting mechanisms at the signal-transmitting stations for operating the signal-receiving apparatus at the signalreceiving station, polarized electro-magnetic mechanisms at the transmitting stations serving to control the relation ot' the signaltransmitting mechanisms with the line, means governed by the signal -sending mechanisms at the transmitting stations serving normally to exclude the polarized electro-magnetic mechanisms from operative relation with the line and serving, upon the transmission of signals, to bring the polarized electro-inagnetic mechanism at a sending station into circuit relation with the line, the normal connection of the source of unidirectional current with the line being such that current from said source of unidirosas 1.1

rectional current will: operate the electromagnet` at a transmitting station whose signal-sending mechanism has brought saidl electro-magnet into Circuit. relation with the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, when the circuit is altered at a transmitting station, to connect unidirectional current in reverse direction with the line.

7. A signaling system including a transmission line extending ,trom a signal-receiving station to a vplurality ot' signal-transmitting stations, a source oi' unidirectional current in circuit relation with the line, signal-transmitting mechanisms at the nal-transmitting stations for operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to exclude other transmitting stations trom the line, polarized electro-magnets at the transmitting stations for operating said switching devices, means governed by the signal-sending-mechanisms at the transmitting stations serving normally to exclude the polarized electro-magnets from operative relation with the line and serving, upon the transmission ot signals, to bring the polarized electro-magnet at a sending station into circuit relation with the line to operate the associate switching device, the normal connection ofthe source ot' unidirectional current with the line being 4such` that current from said source ot unidirectional current will operate the electro-magnet at a transmitting station whose signa -sending mechanism has brought said eleCtro-magent into circuit relation with the line, an electromagnet at the receiving station normally in circuit relation with the line, mechanism governed by the latter electro-magnet and serving, when the circuit is altered* at a transmitting statio-n, to connect unidirectional current in reverse direction with the line, means for holding the armature of the polarized electro-magnet at the transmitting station from which signals are being sent, in order to maintain the switching mechanism governed by the armature ot said polarized electro-magnet in the condition in which said armature has placed said switching mechanism, and means whereby the signal-sending mechanism may release the armature ot said polarized electro-inagnetwhen said signal-sending mechanism has been restored to normal.

8. A signaling system including a transmission line extending from a signal-receiving station to a plurality ot signal-transinitting stations, a source ot undirectional current in' circuit relation with. the line, signaltransmitting mechanisms at the signaltransmitting stations for operatin-g the signal-receiving vapparatus at the signal-receiving stat-ion, switching devices at the transmitting stations, each serving to exclude other transmitting stations trom the line, polarized electro-magnets at the transmitting stations for operating said switching devices, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the polarized electro-magnets from operative relation with the line and serving, upon the transmission of signals, to bring the polarized electro-magnet at a sending station into circuit relation with the line to operate the associate switching device, the normal connection of the source of unidirectional current with the line being such that current from said source of unidirectional current will operate the electro-magnet at a transmitting station whose signal-sending mechanism has brought said electro-magnet into circuit relation with the line, an electromagnet atthe receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, when the circuit is altered at a transmitting station, to connect unidirec` tional current in reverse direction with the line.

i). signaling system including a transmission line ext-ending trom a signal-receiving station to a plurality of signal-transmitting stations, a source ot unidirectional currentin circuit relation with the line, signal-transmitting mechanisms at the sigmil-transmitting stations for operating the signal-receiving apparatus at the signalreceiving station, switching devices at the transmitting stations, each serving to exclude other transmitting stations trom the line, polarized electro-magnetic mechanisms at the transmitting stations tor operating said switching devices and serving to cor.- trol the relation ot' the signal-trauernitting mechanisms with the line, and servin0',.

when energized, to cause operative association ot' said signal-transmitting mechanisms with the line, means governed by the signalsending mechanisms at the transmitting stations serving normally to exclude the polarized electro-magnetic mechanisms trom operative relation with the line and serving, upon the transmission ot signals, to bring the polarized electro-magnetic mechanism at a sending station into circuit relation with the line to operate the associate switching device, the normal connection ot th(-` source of unidirectional current with the line being such that current from said source ot' unidirectional current will operate tht electro-magnet at a transmitting station whose signal-sending mechanism has brought said electro-magnet into circuit relation with the line, an electro-magnet at the receiving stationl normally in ciicuit relation with the line, mechanism governed by the latter electro-magnet and serving, when the circuit is altered at a transmitting static-n, to connect unidirectional current in reverse direction with the line, means for holding the armature of the polarized electro-magnet at the transmitting station from which signals are being sent, in order to maintain the switching mechanism governed by the armature of said polarized electro-magnetic mechanism in the condition in Which said armature has placed said switching mechanism, and means whereby the signal-sending mechanism may release the armature of said polarized electro-magnetic mechanism when said signal-sending mechanism has been restored to normal.

10. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmitting stations, a source of unidirectional currentin circuit relation ivith the line, signal-transmitting mechanisms at the signal-transmitting stations for operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to eX- clude other transmitting stations from t-he line, polarized electro-magnetic mechanisms at the transmitting stations for operating said switching devices and serving to cont-rol the relation of the signal-transmitting mechanisms With the line, and serving, when energized, to cause operative association of said signal-transmitting mechanisms With the line, means governed by the signal-sending mechanisms at the transmitting stations serving normally t-o exclude the polarized electro-magnetic mechanisms from operative relation With the line and serving, upon the transmission of signals, to bring the polarized electro-magnetic mechanism at a sending station into circuit relation with the line to operate the associate switching device, the normal connection of the source of unidirectional current with the line being such that current from said source ot unidirectional current will operate the electromagnet at a transmitting station Whose signal-sending mechanism has brought said electro-magnet into circuit relation With the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, when the circuit is altered at a transmitting station, to connect unidirectional current in reverse direction with the line.

ll. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmitting stations, a source of unidirectional current in circuit relation With the line, signal-transmitting mechanisms at the signal-transmitting stations for operating the signal-receiving apparatus at the signal-receiving station, polarized electro-magnets at the transmitting stations, means governed by the signal-sending `mechanisms at the transmitting stations serving normally to exclude the polarized electro-magnets from operative relation with the line and serving, upon the transmission of signals, to bring the polarized electro-magnet at a sending station into circuit relation With the line, the normal connection of the source of unidirectional current With the line being such that current from said source of unidirectional current Will operate theelectro-magnet at a transmitting station Whose signal-sending mechanism has brought said electro-magnet into circuit relation with the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electromagnet and serving, when the circuit is altered at a transmitting station, to connect d I unidirectional current in reverse direction with the line.

12. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signaltransmitting stations, a source of unidirectional current in circuit relation with the line, lsignal-transmitting mechanisms at the signal-transmitting stations for operating the signal-receiving apparatusat the signalreceiving station, polarized electro-magnetic mechanisms at the transmitting stations serving to control the relation of the signaltransmitting mechanisms with the line, means governed by the signal-sending mechanisms atthe transmitting stations serving normally to exclude the polarized electro-magnetic mechanisms from operative relation with the line and serving, upon the transmission of signals, to bring the polarized electro-magnetic mechanism at a sending station into circuit relation with the line, the normal connection of the source of unidirectional current with the line being such that current from said source of unidirectional current will operate the electromagnet at a transmitting station Whose signal-sending mechanism has brought said electro-magnet into circuit relation with the line, an electro-magnet `at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, When the circuit is altered at a transmitting station, to connect unidirectional current in reverse direction With the line.

13. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmitting stations, a source of unidirectional current in closed circuit with the line, signaltransmitting mechanisms at the signal-transmitting stations for operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to exclude other transmitting stations from the line, polarized electro-magnets adapted to be looped into the line at the transmitting stations for operating said switching devices, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the polarized electro-magnets trom operative relation with the line and serving, upon the transmission of signals, to

v bring the polarized electro-magnet at a sending station into circuit relation with the line to operate the associate switching device, the normal connection of the source of unidirectional current with the line being such that current from said source of unidirectional current will operate the electro-inagnet at a transmitting station whose signalsending mechanism has brought said electromagnet into circuit relation with the line, an electro-magnet at the receiving station normally in circuit relation with the line, mechanism governed by the latter electromagnet and serving, when the circuit is altered at a transmitting station, to connect unidirectional current in reverse direction with the line, means for holding the armature of the polarized electro-magnet at the transmitting station from which signals are being sent, in order to maintain the switching mechanism governed by the armature ot said polarized electro-magnet in the condition`1n which said armature has placed said switching mechanism, and means whereby the signal-sending mechanism may release the armature of said polarized electro-magnet when said signal-sending mechanism has been restored to normal.

14:. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmittino' stations, a source of unidirectional current in closed circuit with the line, signaltransmitting mechanisms at the signal-transmitting stations for operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to exclude other transmitting stations from the line, polarized electro-magnets adapted to be looped into the line at the transmitting stations for operating said switching devices, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the polarized electro-magnets from operative relation with the line and serving, upon the transmission of signals, to bring the polarized electro-magnet at a sending station into circuit relation with the line to operate the associate switching' device, the normal connection of the source of unidirectional current with the line being such that current from said source of unidirectional current will operate the electro-magnet at a transmitting station whose signalsending mechanism has brought said electromagnet into circuit relation with the line, an electro-magnet at the receiving station normally in circuit relation with the line, land mechanism governed by the latter electro-magnet and serving, when the circuit is altered at a transmitting station, to conneet unidirectional current in reverse direction with the line.

l5. A signaling system including a transmission line extending trom a signal-receiving station to a plurality of signal-transmitting stations, a source of unidirectional current in closed circuit with the line, signal-transmitting mechanisms at the signaltransmitting stations for operating the signal-receiving apparatus at the signal-receiving station, switching devices -at the transmitting' stations, each serving to exclude other transmitting stations from the line, polarized electro-magnetic mechanisms adapted to be looped into the line at the transmitting stations for operating said switching' devices and serving to control the relation of the signal-transmitting mechanisms with the line, and serving, when energized, to cause operative association of said signal-transmitting mechanisms with the line, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the polarized electro-magnetic mechanisms .from operative relation with the line and serving, upon the transmission ot signals, to bring the polarized clectro-n'iagnetic mechanism at a sending' station into circuit relation with the line to operate the associate switching device, the normal connection oit the source of unidirectional current with thc line being such that current from said source ot' unidirectional current will operate the electro-magnet at a transmitting station whose signalsending mechanism has brought. said electro-magnet into circuit relation with the line, an electro-magnet at the receiving station normally in circuit relation with the line, mechanism governed by the latter electro-magnet and serving, when the circuit is altered at a transmitting station, to connect unidirectional current in reverse direction with the line, means for holding the armature or' the polarized electro-magnet at the transmitting station from which signals are being sent, in order to maintain the switching mechanism governed by the armature of said polarized electro-magnetic mechanism in the condition in which said armature has placed said switching mechanism, and means whereby the signal-sending mechanism may release the armature ot said polarized electro-magnetic mechanism when said signal-sending mechanism has been restored to normal.

isoV

16. A signaling system including a transmission line extending from a signal-receiving station to a plurality or" signaltransmitting stations, a source ot' unidirectional current in closed circuit With the line, signal-transmitting mechanisms at the signal-transmitting stations for operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to exclude other transmitting'stations from the line, polarized electro-magnetic mechanisms adapted to be looped into the line at the transmitting stations tor operating` said switching devices and serving to control the relation of the signal-transmitting mechanisms with the line, and serving, when energized, to cause operative association of said signal-transmitting mechanisms with the line, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the polarized electro-magnetic mechanisms from operative relation with the line and serving, upon the transmission ot signals, to bring the polarized electro-magnetic mechanism at a sending. station into circuitrelation with the line to operate the associate switching device,the normal connection of the source of unidirectional current With the line being such that current from said source of unidirectional current will operate the electro-magnet at a transmitting station Whose signal-sending mechanism has brought said electro-magnet into circuit relation With the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, when the circuit is altered at a transmitting station, to connect unidirectional current in reverse direction With the line.

17. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmitting stations, a source of unidirectional current in closed circuit with the line, signaltransmitting mechanisms at the sig-naltransmitting stations for operat-ing the signal-receiving apparatus at the signal-receiving station, polarized electro-magnets adapt-- ed to be. looped into the line at the transmitting stations, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the polarized electro-magnets from operative relation With the line and serving, upon the transmission of signals, to bring the polarized electro-magnet at a' sending station into circuit relation with the line, the normal connection of the source of unidirectional current with the line being such that current from said source of unidirectional current will operate the electro-magnet at a transmitting station Whose signal-sendtransmitting stations, a source of unidirec.

tional current in closed circuit with the line, signal-transmitting mechanisms at the signal-transmitting stations for operating'the signal-receiving apparatus at the signalreceiving station, polarized electro-magnetic mechanisms adapted to be looped into the line at the transmit-ting stations serving to control the relation of the signal-trans-l mitting mechanisms ivith the line, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the polarized electro-magnetic mechanisms from operative relation with the line and serving, upon the transmission of signals, to bring the polarized electro-magnetic mechanism at a sending station into circuit relation With the line, the normal connection of the source of unidirectional current With the line being such that current from said source of unidirectional current Will operate the electro-,magnet at a transmitting station Whose signalsending mechanism has brought said electro-magnet into circuit relation with the line, an electro-magnet at the receiving station normally in circuit relation With the line, and mechanism governed by the latter electro-magnet and serving, when the circuit'is altered at a transmitting stat-ion, to connect unidirectional current in reverse direction With the line.

19. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmitting stations, a source of unidirectional current in closed circuit With the line, signal-transmitting mechanisms at the signaltransmitting stations for operating the signal-receiving apparatus at the signal-receiving station, polarized electro-magnetic mechanisms adapted to be looped into the line at the transmitting stations serving to control the relation of the signal-transmitting mechanisms With the line, the normal connection of the source of unidirectional current with the line being such that current from said source of unidirectional current Will operate the electro-magnet at a transmitting station from Which signals are being sent, an electro-magnet at the receiving station normally in circuit relation With the line, and mechanism governed by the latter electro-magnet and serving, when the circuit is altered at a transmitting station, to connect unidirectional current in reverse direction with the line.

20. A signaling system including a transmission line extending trom a signal-receiving station to a plurality of signal-transmitting stations, a source of unidirectional current in circuit relation with the line, signaltransmitting mechanisms at the signaltransmitting stations tor operating the signal-receiving apparatus at the signal -receiving station, switching devices at the transmitting stations, each serving to exclude other transmitting stations from the line, polarized electro-magnets adapted to be looped into the line at the transmitting stations for operating said switching devices, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the polarized electromagnets trom operative relation with the line and serving, upon the transmission otl signals, to bring the polarized electro-inagnet at a sending station into circuit relation with the line to operate the associate switching device, the normal connection of the source ot unidirectional current with the line being such that current from said source of unidirectional current will operate the electro-magnet at a transmitting station whose signalsending mechanism has brought said electro-magnet into circuit relation with the line, an electro-magnet at the receiving station normally in circuit relation with the line, mechanism governed by the latter electro-magnet and serving, when the circuit is altered at a transmitting station, to connect unidirectional current in reverse direction with the line, means tor holding the armature ot the polarized electro-magnet at the transmitting station from which signals are being sent, in order to maintain the switching mechanism governed by the armature of said polarized electromagnet in the condition in which said armature has placed said switching mechanism, and means whereby the signal-sending mechanism may release the armature of said polarized electro-magnet when said signalsending mechanism has been restored to normal.

21. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmitting stations, a source of unidirectional current in circuit relation with the line, signal-transmitting mechanisms at the signaltransmitting stations for operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to exclude other transmitting stations from the line, polarized electro-magnets adapted to be looped into the line at the transmitting stations for operating said switching devices, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the polarized electro-magnets from cperativerelation with the line and serving, upon the transmission ot signals, to bring the polarized electro-magnet at a sending station into cir-l cuit relation with the line to operate the associate switching device, the normal connection of the source of unidirectional current with the line being such that current from said source of unidirectional current will operate the electro-magnet at a transmitting station whose signal-.sending mechanism has brought said electro-magnet into circuit relation with the line, an electromagnet at the receiving station normally in circuit relation with the line, and mecha-- nism governed by the latter electro-magnet and serving, when the circuit is altered at a transmitting station, to connect unidirectional current in reverse direction with the line.

22. A signaling system including a transmission line extending trom a signal-receiving station to a plurality of signal-transmitting stations, a source ot unidirectional current in circuit relation with the line, signaltransmitting mechanisms at the signaltransmitting stations .tor operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to exclude other transmitting stations from the line, polarized electromagnetic mechanisms adapted to be looped into the line at the transmitting stations for operating said switching devices and serving to control the relation of the signal-transmitting mechanisms with the line, and serving, when energized, to cause operative association ot' said signal-transmitting ,mechanisms with the line, means governed by the signal-sending mechanisms at the transmitting stations serving normally vto exclude the polarized electro-magnetic mechanisms from operative relation with the line and serving, upon the transmission ot-signals, to bring the polarized electro-n'iagnetic mechanism at a sending station into circuit relation with the line to operate the associate switching device, the normal connection oi' the source ot unidirectional current with the line being such that current from said source oi unidirectional current will operate the electro-magnet at a transmitting station whose signal-sending mechanism has' brought said electro-magnetinto circuit relation with the line, an electromagnet at the receiving station normally in circuit relation with the line, mechanism governed by the latter electro-magnet and serving, when the circuit is altered at a transmitting station, to connect unidirectional current in reverse direction with the line, means for holding the armature of the polarized electro-magnet at the transmitting station from which signals are being Ment, in order to maintain the switching mechanism governed by the armature of said polarized electro-magnetic mechanism in the co-ndition in which said armature has placed said switching mechanism, and means whereby the signal-sending mechanism may release the armature of said polarized electro-magnetic mechanism when said signal-sending mechanism has been restored to normal.

23. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmitting stations, a source of unidirectional current in circuit relation With the line, signaltransmittingmechanisms at the signal-transmitting stations for operating the signalreceiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to exclude other transmitting' stations from the line, polarized electro-magnetic -mechanisms adapted to be looped into the line at the transmitting stations for operating said switching` devices and serving to control the relation of the signal-transmitting mechanisms With the line, and serving, when energized, to cause operative association of said signal-transmitting mechanisms with the line, means governed by the signal-sending mechanisms at the transmittingstations serving normally to exclude the polarized electro-magnetic mechanisms from operative relation with the line and serving, upon the transmission ofsignals, to bring the polarized electro-magnetic mechanism at a sending station into circuit relation with the line to operate the associate switching device, the normal connection of the source of unidirectional current witli the line being such that current from said source of unidirectional current Will operate the electro-magnet at a transmitting station Whose signal-sending mechanism has brought said electro-magnet into circuit relation with the line, an electromagnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, When the circuit is altered at a transmitting station, to connect unidirectional current in reverse direction With the line.

24. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmitting stations, a source of unidirectional current in circuit relation with the line, signaltransmitting mechanisms at the signal-transmitting stations for operating the signalreceiving apparatus at the signal-receiving station, polarized electro-magnets adapted to be looped into the line at the transmitting stations, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the polarized electro-magnets from operative relation with the line and serving, upon the transmission of signals, to bring the polarized electromagnet at a sending station into circuit relation With the line, the normal connection of the source of unidirectional current With the line being such that current from said source of unidirectional current will operate the electro-magnet at a transmitting station Whose Y signalsending mechanism has brought said electro-magnet into circuit relation with the line, an electro-magnet at the receiving station normally in circuit relation With the line, and mechanism governed by the latter electro-magnet and serving, when the circuit is altered at a transmitting station, to connect unidirectional current in reverse direction with the line.

25. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmitting stations, a source of unidirectional current in circuit relation with the line, signaltransmitting mechanisms at the signal-transmitting stations for operating the signal-receiving apparatus at the signal-receiving station, polarized electro-magnetic mechanisms adapted to be looped into the line at the transmitting stations serving to control the relation of the signal-transmitting mechanisms With the line, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the polarized electro-magnetic mechanisms from operative relation with the line and serving, upon the transmission of signals, to bring the polarized electro-inagnetic mechanism at a sending station into circuit relation with the line, the normal connection of the source of unidirectional current with the line being such that current from said source of unidirectional current will operate the electro-magnet at a tra-nsmitting station Whose signal-sending mechanism has brought said electro-magnet into circuit relation with the line, an electromagnet at. the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and A control the relation of the signal-transmitting mechanisms with the line, the normal connection of the source of unidirectional current with the line being such that current from said source of unidirectional current will operate the electrosmagnet at a transmitting station from which signals are being sent, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, when the circuit is altered" at a transmitting station, to connect undirect-ional current in reverse direction with the line.

27. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-trans initting stations, a source of current in closed circuit with the line, signal-transmitting mechanisms at the signaltransmitting stations for operating the signal-receiving apparatus at the signal-receiving station, electro-magnetic mechanisms at the transmitting stations serving to/control the relation of the signal-transmitting mechanisms with the line, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the electro-inagnetic mechanisms from operative relation with the line, and serving, upon the trans mission of signals to bring the electro-magnetic mechanism at a sending station into circuit relation with the line to establish ceoperative relation of the signal-transmitting mechanism at the sending station with the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, when circuit is alte-red at a transmitting station, to impress current upon the line which is not adapted to operate said electro-inagnetic mechanisms but which is adapted to cooperate with the signal transmitting mechanisms to occasion signals at the receiving station.

28. A signaling system including a transmission liiie extending from a signal-receiving station to a plurality of signal-transmitting stations, a source of current in closed circuit with the line, signal-transniitting mechanisms at the signal-transmitting stations for operating the signal-receiving apparatus at the signal-receiving station, electro-magnetic mechanisms at the trans-- mitting stations serving to control the relation of the signabtransmitting mechanisms with the line, the signal-transmitting apparatus at a sending station serving to bring the electro-magnetic mechanism at the sending station into circuit relation with the line to establish cooperative relation of the signal-transmitting mechanism at the sending station with the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism govl l t ei-ned by the latter electro-magnet and servwhich is not adapted to operate said electro magnetic mechanisms but which is adapted to coperate with the signal-transmitting mechanisms to occasion signals at the receiving station.

29. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmit ting stations, a source ot current in closed circuit with the line, signal-transmitting mechanisms at the signal-transmitting stations for operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to exclude other transmitting stations from the line, electroniag netic mechanisms at the transmitting Stations tor operating said switching devices, electro-magnetic mechanism at a sending station operating the switching device thereat to exclude the remaining transmitting stations from the line, an electroemagnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, when circuit is altered at a transmitting station, to impress current upon the line which is not adapted to operate said electroemagnetic mechanisms but which is adapted to cooperate with the signal-trans mitting mechanisms to occasion signals at the receiving station.

30. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signabtransmitting stations, a source of current in closed circuit with the line, signaltransmitting mechanisms at the signal-transmitting sta` tions for operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations,`eaeh serving to exclude other transmit-ting stations from the line, electro-inagiietic mechanisms at the transmitting stations tor operating said switching devices and serving to control the relation of the 'signal -transmitting mechanisms with the line, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the electromagnetic mechanisms from operative relation with the line, and serving, upon the transmission of signals to bring the electromagnetic mechanism at a sending station into circuit relation with the line to operate the associate switching device, an electroinagiiet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, when circuit is altered at a transmitting stat-ion, to impress current upon the line which is not adapted to operate said electro-magnetic mechanisms but which is adapted to coperate with the signal-transmitting mechanisms to occasion signals at the receiving station.

31. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmitvting stations, a source of current in circuit relation with the line, signal-transmitting mechanisms at the signal-transmitting stations tor operating the signal-receiving apparatus at the signal-receiving station, electro-magnetic mechanisms at the transmitting stations serving to control the relation of the signal-transmitting mechanisms with the line, means governed by the signal-sending mechanisms at the transmitting stat-ions serving normally to exclude the electro-magnetic mechanisms from operative relation with the line, and serving, upon t-he transmission of signals to bring the electro-magnetic mechanism at a sending stat-ion into circuit relation with the line to establish cooperative relation of t-he signal-transmitting mechanism at the sending station with the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governedby the latter electro-magnet and serving, when circuit is altered at a transmitting station, to impress current upon the line which is not adapted to operate said electro-magnetic mechanisms but which is adapted to coperate with the signal-transmitting mechanisms vto occasion signals at the receiving station.

32. A signaling system including a transmission line extending from a signal-receiving station to a plurality ot signal-transmitting stat-ions, a source of current in circuit relation` with the line, signal-transmitting mechanisms at the signal-transmitting stations for operating the signal-receiving apparatus at the signal-receiving station, elec,- tro-magnet-ic mechanisms at the transmitting stat-ions serving to control the relation of the signal-transmitting mechanisms with theline, the signal-transmitting apparatus at a `sending station serving to bring the electro-magnetic mechanism at the sending'l station into circuit relation with the line to establish coperative relation of the signaltransmitting mechanism at the sending station with the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by thelatter electro-magnet and serving, when circuit is altered at a transmitting station,

-to impress current upon the line which is not adapted to operate said electro-magnetic mechanisms but which is adapted to coperate with the signal-transmitting mechanisms to occasion signals at the receiving station.

33. A signaling system including a transmission line extending from a signal-receivingstation to a plurality of signal-transmitting stations, a source of current in circuit relation with the line, signal-transmitting mechanisms at the signal-transmittingv stations for operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to exclude other transmitting stations from the line, electro-magnetic mechanisms at the transmit-ting stations tor ope-rating said switching devices, electro-magnetic mechanism at a sending station operating the switching device thereat to exclude the remaining transmitting stations rom the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, when circuit is altered at a transmitting station, to impress current upon the line which is not adapted to operate said electro-magnetic mechanisms but which is adapted to cooperate with the signal-transmitting mechanisms to occasion signals at the receiving station.

34. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmitting stations, a source of current in circuit relation with the line, signal-transmitting mechanisms at the signal-transmitting stations for operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to exclude other transmitting stations from the line, electro-magnetic mechanisms atvthe transmitting stations for operating said switching devices and serving to control the relation of the signal-transmitting mechanisms with the line, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the electro-magnetic mechanisms from operative relation with the line, and serving, upon the transmission ot signals to bring the electro-magnetic mechanism at a sending station into circuit relation with the line'to operate the associate switching device, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the'latter electro-magnet and serving, when circuit is altered at a transmitting station, to impress current upon the -line which is not adapted to operate said circuit with the line, signal-transmitting mechanisms at the signal-transmitting stations for operating the signal-receiving apparatus at the signal-receiving station, electro-magnetic mechanisms adapted tor loop connection in the line at the transmitting stations serving to control the relation of the signal-transmitting mechanisms with the line, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the electro-magnetic mechanisms from operative relation with the line, and serving, upon the transmission ot signals to bring the electro-magnetic mechanism at a sending station into circuit relation with the line to establish cooperative relation of the signal-transmitting mechanism at the sending station with the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, when circuit is altered at a transmitting station, to impress current upon the line which is not adapted to operate said electro-magnetic mechanisms hut which is adapted to cooperate with the signal-transmitting mechanisms to occasion signals at the receiving station.

86. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signaltransmitting stations, a source of current in closed circuit with the line, signal-transmitting mechanisms at the signal-transmitting stations for operating the signal-receiving apparatus at the signal-receiving station, electro-magnetic mechanisms adapted for loop connection in the line at the transmitting stations serving to control the relation ot the signal-transmitting mechanisms with the line, the signal-transmitting apparatus at a sending station serving to bring the electro-magnetic mechanism at the sending station into circuit relation with the line to establish cooperative relation of the signaltransmitting mechanism at the sending station with the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, when circuit is altered at a transmitting station, to impress current upon the line which is not adapted to operate said electromagnetic mechanisms but which is adapted to cooperate with the sigi al-transmitting mechanisms to occasion signals at the receiving station.

37. A signaling system including a transmission line extendinov from a signal-receiving station to a plurality of signal-transmitting stations, a source of current in closed circuit with the line, signal-transmitting mechanisms at the signal-transmitting stations for operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to excludel other transmitting stations from the line, electro-magnetic mechanisms adapted for loop connection in the line at the transmitting stations for operating said switching devices, electro-magnetic mechanism at a sending station operating the switch device thereat to exclude the remaining transmitting stat-ions from the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, .when circuit is altered at a transmitting station, to impress current upon the line which is not adapted to operate said electro-magnetic mechanisms but which is adapted to coperate with the signal-transmitting mechanisms to occasion signals at the receiving station.

38. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmitting stations, a source ot current in closed circuit with the line, signal-transmitting mechanisms at the signal-transmitting stations tor operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to exclude other transmitting stations from the line, electro-magnetic mechanisms adapted for loop connection in the line at the transmitting stations, for operating said switching devices and serving to control the relation of the signaltransmitting mechanisms with the line, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the electro-magnetic mechanisms from operative relation with the line, and serving, upon the transmission ot signals to bring the electro-magnetic mechanisin at a sending station into circuit relation with the line to operate the associate switching device, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed hy the latter electro-magnet and serving, when circuit is altered at a transmitting station, to impress current upon the line which is not adapted to operate said electro-magnetic mechanisms but which is adapted to cooperate with the signal-transmitting mechanisms to occasion signals at the receiving station.

39. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signal-transmitting stations, a source of current in circuit relation with the line, signal-transmitting mechanisms at the signal-transmitting stations tor operating the signal-receiving apparatus at the signal-receiving station, electro-magnetic mechanisms adapted for loop connection in the line at the transmitting stations serving to control the relation of the signal-transmitting mechanisms with the line, means governed by the signal-sending mechanisms at the transmitting stations serving normally to exclude the electro-magnetic mechanisms from operative relation with the line, and serving, upon the transmission of signals to bring the electro-magnetic mechanism at a sending station into circuit relation with the line to establish cooperative relation of the signal-transmitting mechanism at the sending stationwith the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, when circuit is altered at a transmitting station, to impress current upon the line which is. not adapted to operate said electro-magnetic mechanisms but which is adapted to coperate wit-h the signal-transmitting mechanisms to occasion signals at the receiving stat-ion.

40. A signaling system including a transmission line extending from a signal-receiving station to a plurality of signaltransmitting stations, a source of current `in circuit relation with the line, signaltransmitting mechanisms at the signaltransmitting stations for operating the signal-receiving apparatus at the signal-receiving station, electro-magnetic mechanisms adapted for loop connection in the line at the transmitting stations serving to control the relation of the signal-transmitting mechanisms with the line, the signaltransmitting apparatus at a sending station servingto bring the electro-magnetic mechanism at the sending station into circuit relation with the line to establish coperative relation of the signal-transmitting mechanism at the sending station with the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving', when circuit is altered at a transmitting station, to impress current upon the line which is not adapted to operate said electro-magnetic mechanisms but which is adapted to cooperate with the signal-transmitting mechanisms to occasion signals at the receiving station.Y

4l. A signaling system including a t 'ansmission line extending from a signal-receiving station to a plurality of signal-transmitting stations, a source of current in circuit relation with the line, signal-transmitting mechanisms at the signal-transmitting stations for operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to exclude other transmitting stations from the line, electro-magnetic mechanisms adapted for loop connection in the line at the transmitting stations for operating said switching devices, electro-magnetic mechanism at a sending station operating the switching device thereat to exclude theremaining transmitting stations rom the line, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electro-magnet and serving, when circuit is altered at a transmitting station, to impress current upon the line which is not adapted to operate said electro-magnetic mechanisms but which is adapted to cooperate with the signal-transmitting mechanisms to occasion signals at the receiving station.

42. A signaling system including a transmission lineextending from a signal-receiving station to a plurality of signal-transmitting stations, a source of current in circuit relation with the line, signal-transmitting mechanisms at the signal-transmitting stations for operating the signal-receiving apparatus at the signal-receiving station, switching devices at the transmitting stations, each serving to exclude other transmitting stations from the line, electro-magnetic mechanisms adapted for loop connection in the line at the transmitting stations for operating said switching devices and serving tocontrol the relation of the signaltransmitting mechanisms with the line, means governed by the mechanisms at the transmitting stations serving normally to exclude the electromagnetic mechanisms from operative relat-ion with the line, and serving, upon the transmission of signals to bring the electromagnetic mechanism at a sending station into circuit relation with the line to operate the associate switching device, an electro-magnet at the receiving station normally in circuit relation with the line, and mechanism governed by the latter electromagnet and serving, when circuit is altered at a transmitting station, to impress current upon the line which is not adapted to operate said electric-magnetic mechanisms but which is adapted to coperate with the signal-transmitting mechanisms to occasion signals at the receiving station.

43. A signaling system including a transmission line extending from transmitting stations to a receiving station, a source of current in closedxcircuit with the line, means for changing the connection of said source of current with the line for operative purposes, a local circuit at the receiving station including the signal-receiver thereat, switching mechanisms entering into the control of said local circuit and operated subsequent to the change of connection of said source of current with ,the line and prior signal-sending to the restoration of the normal connection and the means for governing the association of said source of current With the line, a of said source of current With thel line.` 10 second'svvitching device associated with the In Witness whereof, I hereunto subscribe local circuit at the receiving station and co my name this 21st day of May A. D. 1909.

operating with the :former switching device EDWARD H. LONG. to eiiect control over the local receiving cir- Witnesses:

cuit, and electromagnetic mechanism in the G. L. CRAGG,

line for operating said switching devices L. Gr. STROH.

Copies of this patent :mayI be obtained for iive cents each, by addressing the Commissioner of Patents, Washington, D. C. 

